FIG. 2 shows a typical tab-locked corrugated box 10 having major flaps 11a and 11b and minor flaps 12a and 12b. The major and minor flaps are held tightly to the sides of the corrugated cardboard box by small tabs 13a and 13b of cardboard which is not removed during the die cutting operation when box 10 was manufactured.
The use of these now widely available tab-locked corrugated boxes adds greatly to the efficiency of the production line. Tab-locked boxes eliminate the need for flap controls on conventionally employed uncasing and case packing machines as well as on the conveyor system. Generally, cardboard boxes of this nature are filled with product through the use of a vertical case packer. Again, when using tabs, such packers require no flap control devices. In fact, no flap control is required anyplace in the processing line until the tabs are broken just prior the case sealer.
Unfortunately, there has not been a device for the efficient cutting or breaking of tabs and giving control of the major and minor flaps. Prior devices have included mechanical expedients to rip the tabs apart by lifting the major and minor flaps of these boxes. Such an operation can easily damage the case and result in a ragged flap edge where the tabs appeared. Further, vacuum devices have been employed where suction cups have been drawn to the flap surfaces and pulled to again physically break the tabs just prior to the sealing operation. Even in this case, however, the flat edges are aesthetically imperfect and the supporting hardware necessary in establishing the required vacuum proved cumbersome and unreliable. To complicated matters, such devices have proven most inadequate when dealing with damp or wet boxes which are most often encountered in high humidity areas. In such a condition, the boxes tend to deform rather than facility a clean tab release. Prior devices have even employed knives, but they have been held in a stationary or moving but fixed orientation to the box and, as a result, have not proven reliable in entering the space between the flap and box to cut the tab. Such devices also were incapable of compensating for boxes of varying widths and would, at times, cut the box flaps themselves rather than just the tabs.
It is thus an object of the present invention to provide a device for the releasing of tabs currently found on the diagonally facing corners of tab-locked corrugated cardboard boxes while avoiding the limitations found in prior art devices.
It is yet a further object of the present invention to provide a device for the releasing of tabs on even cardboard boxes that are deformed.